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1.
Phys Rev Lett ; 132(22): 222501, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38877923

RESUMEN

The known I^{π}=8_{1}^{+}, E_{x}=2129-keV isomer in the semimagic nucleus ^{130}Cd_{82} was populated in the projectile fission of a ^{238}U beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, E_{x}=2001.2(7) keV, and half-life, T_{1/2}=57(3) ns, of the I^{π}=6_{1}^{+} state based on γγ coincidence information. Furthermore, the half-life of the 8_{1}^{+} state, T_{1/2}=224(4) ns, was remeasured with high precision. The new experimental information, combined with available data for ^{134}Sn and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for ^{132}Sn, a doubly magic nucleus far-off stability. A comparison to analogous information for ^{100}Sn provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.

2.
S Afr Med J ; 112(5): 341-346, 2022 04 29.
Artículo en Inglés | MEDLINE | ID: mdl-35587247

RESUMEN

BACKGROUND: In South Africa (SA), adolescent girls and young women (AGYW) aged 15 - 24 years account for nearly 25% of all new HIV infections in the country. The intersection of substance use and sexual risk continues to drive the HIV epidemic among AGYW. For example, methaqualone, also known as Mandrax, has sedative effects that may affect women's ability to negotiate condom use during sex, refuse sex without a condom, or consent to sex, thereby increasing their risk for HIV. Consequently, it is critical to understand how Mandrax use affects HIV risk among AGYW and to assess awareness of and willingness to use biomedical HIV prevention methods, such as pre-exposure prophylaxis (PrEP), among AGYW who use Mandrax. OBJECTIVES: To examine the role of Mandrax use in sexual behaviours and investigate the extent to which AGYW who use Mandrax are aware of and willing to initiate PrEP. METHODS: Data for this report were derived from baseline and 6-month follow-up data provided by 500 AGYW participating in a cluster-randomised trial assessing the efficacy of a young woman-focused intervention to reduce substance use and HIV risk. AGYW who self-identified as black African or coloured, reported using substances, reported condomless sex in the past 3 months, and had discontinued school early were recruited from 24 community clusters across Cape Town, SA. Following consent/assent, participants provided biological specimens to test for recent drug use (including Mandrax) and completed the self-report questionnaire. RESULTS: Logistic regression analysis revealed that the AGYW who had a positive test result for Mandrax use were less likely to use a condom with their main partner (p=0.01), and almost three times more likely to use alcohol and/or other drugs before or during their last act of sexual intercourse (p<0.001), compared with the AGYW who had a negative Mandrax test result. Mandrax use was not significantly related to PrEP awareness (p>0.10) or willingness to use PrEP (p>0.10), but 70% of AGYW who used Mandrax were willing to initiate PrEP. CONCLUSION: The study findings highlight how Mandrax use may contribute to HIV risk among SA AGYW. Key decision-makers should consider incorporating substance use prevention efforts into existing HIV reduction programmes and equip youth-friendly clinics with the resources to identify AGYW who use Mandrax and offer them PrEP.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Profilaxis Pre-Exposición , Trastornos Relacionados con Sustancias , Adolescente , Fármacos Anti-VIH/uso terapéutico , Difenhidramina , Combinación de Medicamentos , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Humanos , Metacualona/uso terapéutico , Profilaxis Pre-Exposición/métodos , Conducta Sexual , Sudáfrica/epidemiología
3.
Phys Rev Lett ; 129(26): 262501, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36608181

RESUMEN

The one-neutron knockout from ^{52}Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states in ^{51}Ca and the momentum distributions corresponding to the removal of 1f_{7/2} and 2p_{3/2} neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f_{7/2} and 2p_{3/2} orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p_{3/2} orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.

4.
Phys Rev Lett ; 126(25): 252501, 2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-34241497

RESUMEN

Direct proton-knockout reactions of ^{55}Sc at ∼220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of ^{54}Ca were investigated through γ-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological internucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the ^{55}Sc ground state with states in ^{54}Ca. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of ^{55}Sc, valence proton removals populated predominantly the ground state of ^{54}Ca. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

6.
Phys Rev Lett ; 125(1): 012501, 2020 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-32678621

RESUMEN

Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250 MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p,3p) over (p,2p) inclusive cross sections follow the trend of other many-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei.

7.
Phys Rev Lett ; 124(22): 222504, 2020 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-32567915

RESUMEN

We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.

8.
Phys Rev Lett ; 124(22): 222501, 2020 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-32567911

RESUMEN

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of ß∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

9.
J Racial Ethn Health Disparities ; 7(6): 1150-1159, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32297304

RESUMEN

INTRODUCTION: An abundance of research investigates the health of often referred to as "at risk" or "high risk" youth from underserved communities and usually racial/ethnic minorities. These ubiquitous terms relate to poverty, violence, and unsafe behaviors (e.g., sex without condoms, alcohol, and drug use). METHODS: This analysis distinguished the heterogeneity of risks among African American female adolescents recruited for an intervention study from underserved communities in North Carolina. Eligibility included: ages 16-19, considered or dropped out of school, never completed high school, and during the past 3 months had sex with a male partner and used drugs or alcohol. A variable was created to represent the continuum of risk comprised of history of homelessness, or trading sex, or current heavy alcohol and marijuana use. Participants fell into 0, 1, or 2-3 categories. Ordinal logistic regression estimated the odds of adverse poor outcomes by category. Linear regression estimated reduction in material and emotional support by category. RESULTS: Of the 237 participants, 59.5%, 27.8%, and 12.7% were in 0, 1, or 2-3 categories, respectively. Relative to adolescents in 0 categories, participants in other categories were more likely to report food insecurity (OR = 3.27, 95%CI [1.8, 5.94]); past arrest (OR = 3.56 [2.08, 6.09]); run away (OR = 3.30 [1.79, 6.10]); multiple sex partners (2.97 [1.61, 5.48]); and vaginal/anal sexual abuse (OR = 3.21[1.73, 5.96]). Material and emotional support was significantly lower for participants in 2-3 risk categories. CONCLUSIONS: Vague use of "at risk" fails to recognize the heterogeneity of experiences and needs of underserved African American youth.


Asunto(s)
Negro o Afroamericano , Asunción de Riesgos , Adolescente , Femenino , Humanos , Modelos Logísticos , North Carolina , Pobreza , Conducta Sexual , Trastornos Relacionados con Sustancias , Encuestas y Cuestionarios , Adulto Joven
10.
S Afr Med J ; 111(1): 40-45, 2020 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-33404004

RESUMEN

BACKGROUND: There is a high prevalence of substance use among youth in South Africa (SA), and adolescent girls and young women (AGYW) experience high rates of depression and anxiety. Substance use behaviours and mental health are associated with other public health problems among AGYW such as HIV and unintended pregnancy. Therefore, understanding the relationship between substance use and mental health is imperative to improve AGYW's health. OBJECTIVES: To examine the association between heavy drinking, marijuana, methamphetamine and methaqualone (Mandrax) use and depressive and anxiety symptoms among AGYW aged 16 - 19 years who have dropped out of school in Cape Town, SA. METHODS: Data for this report come from the baseline data of 500 participants of an ongoing cluster-randomised trial assessing the efficacy of a young woman-focused intervention to reduce substance use and HIV risk. After AGYW consented/assented to participate, they completed a urine drug screen and a baseline questionnaire. RESULTS: Logistic and negative binomial regressions, controlling for clustering at the neighbourhood level, revealed that frequency of depressive symptoms was significantly and positively related to a positive drug screen for Mandrax (ß=0.07; p=0.03). All other associations between the frequency of depressive symptoms and substance use were not statistically significant (ps>0.05). The associations between frequency of anxiety symptoms and substance use were not statistically significant (ps>0.05). CONCLUSIONS: Our findings highlight the need to address substance use, especially Mandrax use and its associated risk, and depression in an integrated, youth-friendly setting.


Asunto(s)
Consumo de Bebidas Alcohólicas/epidemiología , Ansiedad/epidemiología , Depresión/epidemiología , Trastornos Relacionados con Sustancias/epidemiología , Adolescente , Femenino , Infecciones por VIH/epidemiología , Humanos , Salud Mental , Prevalencia , Sudáfrica/epidemiología , Detección de Abuso de Sustancias , Encuestas y Cuestionarios , Adulto Joven
11.
Phys Rev Lett ; 123(14): 142501, 2019 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-31702209

RESUMEN

Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a ^{54}Ca beam striking on a liquid hydrogen target at ∼200 MeV/u. A significantly larger cross section to the p_{3/2} state compared to the f_{5/2} state observed in the excitation of ^{53}Ca provides direct evidence for the nature of the N=34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

12.
Phys Rev Lett ; 122(22): 222502, 2019 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-31283269

RESUMEN

A record number of ^{100}Sn nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the ß-decay end point energy of ^{100}Sn were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0^{+}→1^{+} Gamow-Teller decay was improved to B_{GT}=4.4_{-0.7}^{+0.9}. A discrimination between different model calculations was possible for the first time, and the level scheme of ^{100}In is investigated further.

13.
Phys Rev Lett ; 122(21): 212502, 2019 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-31283301

RESUMEN

The ß-delayed γ-ray spectroscopy of neutron-rich ^{123,125}Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2^{-} ß-emitting isomers in ^{123,125}Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2^{+} and 1/2^{-} levels is extended in Ag isotopes up to N=78, providing a clear signal for the reduction of the Z=40 subshell gap in Ag towards N=82. Shell-model calculations with the state-of-the-art V_{MU} plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in ^{123,125}Ag. The tensor force is found to play a crucial role in the evolution of the size of the Z=40 subshell gap. The observed inversion of the single-particle levels around ^{123}Ag can be well interpreted in terms of the monopole shift of the π1g_{9/2} orbitals mainly caused by the increasing occupation of ν1h_{11/2} orbitals.

14.
Orphanet J Rare Dis ; 14(1): 133, 2019 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-31186066

RESUMEN

Epidermolysis Bullosa (EB) is a group of rare genetic disorders resulting in skin fragility and other symptoms. Commissioned by DEBRA International and funded by DEBRA Norway, this evidence-bases guideline provides recommendations to optimise psychosocial wellbeing in EB.An international multidisciplinary panel of social and health care professionals (HCP) and people living with EB was formed. A systematic international literature review was conducted by the panel following the Scottish Intercollegiate Guidelines Network (SIGN) methodology. The resulting papers underwent systematic selection and critique processes. Included papers were allocated to 6 different outcome groups to allow data synthesis and exploration: quality of life, coping, family, wellbeing, access to HCP and pain. Based on the evidence in those papers, recommendations were made for individuals living with EB, family and caregivers and HCP working in the field.Few studies have investigated interventions and which factors lead to better outcomes, but general recommendations can be made. EB is a complex disease impacting enormously on every aspect of psychosocial life. People and families living with EB need access to multidisciplinary support, including psychological guidance, in order to improve quality of life and psychosocial wellbeing. Interventions should stimulate social participation to prevent isolation. People with EB and their families should be able to access a supportive network. HCP should be well supported and educated about the complexity of EB. They should work collaboratively with those around the individual with EB (e.g. schools, employers etc.) to provide psychosocial opportunity and care.Attention should be paid to the psychosocial impact of EB as well as physical needs. Directions for research are indicated.


Asunto(s)
Epidermólisis Ampollosa/psicología , Adaptación Psicológica/fisiología , Epidermólisis Ampollosa/fisiopatología , Humanos , Calidad de Vida
15.
Nature ; 569(7754): 53-58, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31043730

RESUMEN

Nuclear magic numbers correspond to fully occupied energy shells of protons or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. Although the sequence of magic numbers is well established for stable nuclei, experimental evidence has revealed modifications for nuclei with a large asymmetry between proton and neutron numbers. Here we provide a spectroscopic study of the doubly magic nucleus 78Ni, which contains fourteen neutrons more than the heaviest stable nickel isotope. We provide direct evidence of its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective-field theory interactions and the quasi-particle random-phase approximation. Our results also indicate the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting a rapid transition from spherical to deformed ground states, with 78Ni as the turning point.

16.
Phys Rev Lett ; 122(16): 162503, 2019 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-31075035

RESUMEN

Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at ∼250 MeV/nucleon are measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons as compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting, contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei.

17.
Phys Rev Lett ; 122(7): 072502, 2019 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-30848641

RESUMEN

The first γ-ray spectroscopy of ^{52}Ar, with the neutron number N=34, was measured using the ^{53}K(p,2p) one-proton removal reaction at ∼210 MeV/u at the RIBF facility. The 2_{1}^{+} excitation energy is found at 1656(18) keV, the highest among the Ar isotopes with N>20. This result is the first experimental signature of the persistence of the N=34 subshell closure beyond ^{54}Ca, i.e., below the magic proton number Z=20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2_{1}^{+} systematics of neutron-rich Ar isotopes, and support a N=34 subshell closure in ^{52}Ar.

18.
Phys Rev Lett ; 122(5): 052501, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30822018

RESUMEN

One of the most exotic light neutron-rich nuclei currently accessible for experimental study is ^{40}Mg, which lies at the intersection of the nucleon magic number N=28 and the neutron drip line. Low-lying excited states of ^{40}Mg have been studied for the first time following a one-proton removal reaction from ^{41}Al, performed at the Radioactive Isotope Beam Factory of RIKEN Nishina Center with the DALI2 γ-ray array and the ZeroDegree spectrometer. Two γ-ray transitions were observed, suggesting an excitation spectrum that shows unexpected properties as compared to both the systematics along the Z=12, N≥20 Mg isotopes and available state-of-the-art theoretical model predictions. A possible explanation for the observed structure involves weak-binding effects in the low-lying excitation spectrum.

20.
Br J Dermatol ; 179(5): 1135-1140, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29949203

RESUMEN

BACKGROUND: Midface toddler excoriation syndrome (MiTES) is a condition recently reported in three unrelated children. Habitual scratching from the first year of life inflicted deep, chronic, scarring wounds around the nose and eyes. One child had a mild neurological deficit but there was no other evidence of insensitivity to pain. Bilateral distribution and localization to the midface distinguish MiTES from other causes of self-inflicted skin damage such as trigeminal trophic syndrome. An earlier study of five siblings from a consanguineous Irish family, with lesions corresponding to MiTES plus other sensory deficits, showed homozygous mutations in a gene for hereditary sensory and autonomic neuropathy type VIII (HSAN8), PRDM12. OBJECTIVES: To study further cases of MiTES, including analysis of PRDM12. METHODS: We describe five further children, from four families, with facial lesions typical of MiTES, in whom mutation analysis of PRDM12 was carried out. RESULTS: Homozygous or compound heterozygous pathogenic expansions of the PRDM12 polyalanine tract were found in four of five affected individuals, in three families. CONCLUSIONS: Our finding of autosomal recessive mutations in PRDM12 in four of five patients with MiTES extends the phenotypic spectrum of PRDM12 mutations, which usually cause HSAN8, characterized by mutilating self-inflicted wounds of the extremities, lips and tongue. By contrast, MiTES shows severe midfacial lesions with little if any evidence of generalized pain insensitivity. The condition is probably genetically heterogeneous, and other congenital insensitivity to pain and HSAN genes such as SCN11A may be implicated. This new understanding of the nature of MiTES, which can masquerade as factitious disease, will facilitate appropriate management.


Asunto(s)
Proteínas Portadoras/genética , Genes Recesivos/genética , Proteínas del Tejido Nervioso/genética , Insensibilidad Congénita al Dolor/genética , Automutilación/etiología , Alelos , Preescolar , Consanguinidad , Análisis Mutacional de ADN , Cara , Femenino , Humanos , Lactante , Masculino , Mutación , Insensibilidad Congénita al Dolor/complicaciones , Síndrome
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